g1cli v0.8.0-g1-RC2 — nostr branch

New features:
- On-chain remark command (system.remark)
- Transfer with comment (--comment flag, atomic batch)
- Nostr profile management (get/set/export)
- Multi-format key export (nostr/ipfs/bitcoin/monero)
- --no-password for non-interactive vault access
- --g1v1-id/--g1v1-password for scripted vault import

Build:
- Rust 1.94.0 minimum
- Binaries: linux-amd64, linux-arm64